Hubbard, T.D.Braun, M.L.Westbrook, R.E.Gallagher, P.E.2011High-resolution lidar data for infrastructure corridors, Tanana Quadrangle, Alaskaraster digital dataRaw Data FileRDF 2011-3GFairbanks, Alaska USAState of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveyshttp://dx.doi.org/10.14509/23004Hubbard, T.D.Koehler, R.D.Combellick, R.A.2011High-resolution lidar data for Alaska infrastructure corridorsRaw Data FileRDF 2011-3Fairbanks, AK USAState of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveyshttp://dx.doi.org/10.14509/22722In advance of design, permitting, and construction of a pipeline to deliver North Slope natural gas to out-of-state customers and Alaska communities, the Division of Geological & Geophysical Surveys (DGGS) has acquired lidar (light detection and ranging) data along proposed pipeline routes, nearby areas of infrastructure, and regions where significant geologic hazards have been identified. Lidar data will serve multiple purposes, but have primarily been collected to (1) evaluate active faulting, slope instability, thaw settlement, erosion, and other engineering constraints along proposed pipeline routes, and (2) provide a base layer for the state-federal GIS database that will be used to evaluate permit applications and construction plans. The vegetation digital surface models (veg_DSM) represent the above ground elevation of the highest laser return with all vegetation greater than 20 cm above the ground included.Provide high resolution terrain elevation and land cover elevation data.
This metadata file was written to document and describe, as a whole, all of the veg_DSM files generated for this project. The original metadata files provided by Watershed Sciences, Inc are also included in the download package and may provide additional useful information that is specific to each file. The metadata files provided by Watershed Sciences, Inc. have not been reviewed for accuracy or compliance with FGDC standards. For each data delivery area, reports documenting data collection methodology, accuracy, and quality control were provided by Watershed Sciences and the Oregon Department of Geology and Mineral Industries (DOGAMI). These reports have been combined into single comprehensive reports organized by delivery region. The lidar QC report (the comprehensive report from DOGAMI) and the lidar delivery report (the comprehensive report from Watershed Sciences) can be found at http://dx.doi.org/10.14509/22722. Information about the quadrangles included in individual delivery regions can be found in the lidar delivery index report included with the data download. The DGGS metadata standard extends the FGDC standard to include several elements that are required to facilitate internal data management. These elements are referred to as layers. This dataset is described as a single layer titled:
>veg_dsm vegetation digital surface model raster image
20102011ground conditionCompleteAs needed-153-1506665ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAlaska PipelineGaslineGeomorphologyLidarProposed Natural Gas PipelineRemote SensingRaster ImageDigital Surface Model (DSM)Vegetation Digital Surface Model (DSM)Alaska Division of Geological & Geophysical SurveysTanana QuadrangleAlaska Highway CorridorAlaska, State ofTrans-Alaska PipelineThe dataset(s) is (are) available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.Alaska Division of Geological & Geophysical SurveysGIS Data Manager/GIS Analystmailing and physical address3354 College RdFairbanksAK99709-3707USA907-451-5029907-451-5020Data collection was supported by funding from the Department of Natural Resources (DNR), Division of Geological & Geophysical Surveys (DGGS), the Alaska Gas Pipeline Project Office, the Office of the Federal Coordinator, and the Alaska Gasline Development Corporation (AGDC). Lidar data were collected and processed by Watershed Sciences, Inc. of Corvallis, OR. Survey data were collected by McClintock Land Associates of Eagle River, AK. Lidar data and derivative products were checked for quality, completeness, and accuracy by State of Oregon Department of Geology & Mineral Industries based in Portland, OR.Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3000Absolute accuracy refers to the mean vertical offset of lidar data relative to measured ground-control points (GCP) obtained throughout the lidar sampling area. Ground control points were collected by McClintock Land Associates, a licensed surveying company, to be used as control comparison with lidar elevations. Refer to the lidar delivery report and lidar QC report for more details on the accuracy of the lidar data for each delivery area, including a comparison of GCP elevations with bare-earth digital elevation model elevations. The veg_DSM grid cell size is 1 meter. The elevation units are in meters.Lidar data have been examined to ensure that overlapping flight lines have consistent elevation values. Project specifications require that lidar consistency, measured as vertical offsets between adjacent flight lines, must average less than 0.15 meters. Refer to the lidar QC report and the lidar delivery report for statistics from consistency analyses for individual delivery sets. Flight lines have been examined to ensure that there was at least 60% sidelap and that there are no data gaps. Shaded relief, lidar slope, and bare-earth digital elevation model (DEM) images have been visually inspected for data errors such as pits, border artifacts, gaps, and shifting. All grids were loaded and inspected for outlier/erroneous percent cover values. All file naming conventions and formats have been checked for consistency. Shaded relief images have been visually inspected for data errors such as pits, border artifacts, gaps, and shifting.Lidar data have been checked for accuracy and completeness. Please refer to the lidar delivery report and lidar QC report for details about data accuracy completeness for individual delivery sets.True horizontal accuracy is regarded as a product of the lidar ground footprint. Lidar is referenced to co-acquired GPS base station data that have accuracies far greater than the value of the lidar footprint. The ground footprint is equal to 1/3333rd of the above - ground flying height. The ground footprint for data collected for this project exceeds typical accuracy of ground control used to reference the lidar data (less than 0.01 meters). Project specifications require the lidar footprint to be between 0.15 and 0.40 meters. Refer to the lidar QC report and lidar delivery report for additional information on horizontal accuracy for individual delivery areas.Vertical accuracy refers to the elevation difference between measured GPS control data and lidar digital elevation models. Project specifications require the root mean square vertical offset to be less than 0.2 meters. The veg_DSM represent the earth's surface with all vegetation points where the vertical accuracy is a function of the accuracy of the bare-earth digital elevation model and the accuracy of lidar vegetation returns. Please see the lidar QC report and lidar delivery report for specific information about accuracy and quality of lidar data, including a comparison of GCP elevations with bare-earth digital elevation model elevations.Acquisition: The lidar data were collected between September and October 2010 and between May and July 2011.The survey used the Leica ALS60 system. Near-nadir scan angles were used to increase penetration of vegetation to ground surfaces. Ground-level GPS and aircraft IMU were collected during the flight.2010 and 2011Processing lidar data: (1) Flight lines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points. (2) Laser point-return coordinates were computed using ALS Post Processor software, IPAS Pro GPS/INS software, and Waypoint GPS, based on independent data from the lidar system, IMU, and aircraft. (3) The raw lidar file was assembled into flight lines per return with each point having an associated x, y, and z coordinate. (4) Visual inspection of swath-to-swath laser point consistencies in the study area were used to perform manual refinements of system alignment. (5) Custom algorithms were designed to evaluate points between adjacent flight lines. Automated system alignment was computed based on randomly selected swath-to-swath accuracy measurements that consider elevation, slope, and intensities. Specifically, refinement in the combination of system pitch, roll, and yaw-offset parameters optimize internal consistency. (6) Noise (e.g., pits and birds) was filtered using ALS post processing software, based on known elevation ranges, and included the removal of any cycle slips.2010, 2011, 2012Hydro-flattening: A combination of automated and manual detection and adjustment techniques was used to identify lake boundaries and water levels for closed water bodies with a surface area > 150 square meters. Boundary polygons were developed using an algorithm that weights lidar-derived slopes, intensities, and return densities to detect the lake edge. Once detected, lake edges were manually reviewed and edited in a 3-D environment, and polygons were created with elevations computed from the filtered lidar returns. During the initial ground-modeling process returns from the water surface within each polygon were filtered and inspected for false low points. The elevation of each lake was computed as 5 cm above the minimum elevation of filtered-water surface cells within the lake polygon. Lake-boundary polygons were then incorporated into the final terrain model and enforced as hard breaklines. The initial ground classified-points falling within lake polygons were reclassified as water points and omitted from the final bare-earth DEM.2010, 2011, 2012Creation of bare-earth DEMs: (1) The TerraScan software suite was used to classify near-ground points. Geometric constraints were used to remove all points not near the earth. The resulting bare-earth ground model was then visually inspected and additional ground modeling was performed in site-specific areas to improve ground detail. (2) The corrected and filtered return points were compared to the real-time kinematic (RTK) ground survey points collected to verify the vertical and horizontal accuracies. (3) Points were output as laser points, TINed and grided surfaces.2011, 2012The vegetation DSMs were derived from LiDAR data using the highest hit method.2011A metadata file was created to generally describe data acquisition of lidar and also to describe the creation of veg_DSM images for the entire project.2012RasterGrid CellUniversal Transverse Mercator50.999600-1530.000000500000.0000000.000000row and column11metersveg_dsmNorth American Datum of 1983Geodetic Reference System 806378137298.257222North American Vertical Datum of 19880.0000001metersAttribute valuesveg_dsmvegetation digital surface model raster imagethis reportveg_dsmThere are no attributes other than the encoded values for easting and northing coordinates.this reportveg_dsmState of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveysmailing and physical3354 College RoadFairbanksAK99709-3707USA907-451-5020907-451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.RDF 2011-3GThe State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity, whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product.Current publication is not available on paper. To purchase other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard.contact DGGS for current pricingGRIDhttp://dx.doi.org/10.14509/23004Free downloadDGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media over the counter, by mail, phone, fax, or email from the DGGS Fairbanks office. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for exact shipping amount.20120217Metadata managermailing and physicalState of Alaska, Department of Natural Resources, Division of Geological & Geophysical SurveysFairbanksAK99709-3707USA907-451-5020FGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If the user has modified this metadata file in any way, the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent this metadata file, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.http://www.dggs.alaska.gov/metadata/dggs.extdggs metadata extensions